Simplified muffler shell construction



Aug. 11, 1970 s w 3,523,590

SIMPLIFIED MUFFLER SHELL CONSTRUCTION Filed Dec. 18, 1968 3 Sheets-Sheet 1 L 4 INVENTOR. ZZZ/ad 6 Siraw V x9 TG/T/VEYS.

1970 E. cs. STRAW 3,523,590

- SIMPLIFIED MUFFLER SHELL CONSTRUCTION Filed Dec. 18, 1968 I5 Sheets-Sheet 2 INVENTOR- TdK/VEYS Aug. 11, 1970 E. G. STRAW SIMPLIFIED MUFFLER SHELL CONSTRUCTION Filed Dec. 18, 196 8 3 Sheets-Sheet 5 gigs.

United States Patent US. Cl. 181-61 9 Claims ABSTRACT OF THE DISCLOSURE This application discloses several embodiments of mufflers for internal combustion engines and methods for forming such mufliers. The mufllers are comprised of a thin wall tubular outer shell that has integrally deformed end sections that terminate at and define circular openings. A tubular member is inserted into each of the end openings or is juxtaposed to the openings to form a ,connecton for an adjacent component of the exhaust system. Each tubular member is fixed around its periphery to the outer shell end section adjacent the opening.

RELATED APPLICATION This application is a continuation-in-part of my application Ser. No. 439,416, filed Mar. 12, 1965, now abandoned.

BRIEF SUMMARY OF THE INVENTION This invention relates to a construction for connecting flow members and method for producing such a connecting construction and more particularly to a construction for joining members having different sizes that does not require extensive forming operations. 7

Frequently it is necessary to join flow conduits having different cross-sectional shapes. For example, the connection between a mufller and a tailpipe in an automotive exhaust system requires a reducing bushing at the connection between the larger diameter shell of the muffier and the smaller diameter portion of the adjacent tailpipe. One conventional manner by which such bushings have been formed requires successive forming operations upon the outer shell of the muffler to reduce its diameter to the diameter of the adjacent tailpipe and turn it outwardly so that an extending bushing portion is provided for connection to the tailpipe. There are several disadvantages to this type of construction. Aside from the cost involved with the successive forming operations, this type of bushing formation places considerable stress upon the deformed member in the area of the bushing. Either a heavier gauge material must be provided to resist the stresses or high scrappage results. Therefore, the cost penalty of this type of construction is accentuated.

It is, therefore, a principal object of this invention to provide an improved construction for coupling members of different diameters together.

It is still a further object of this invention to provide an improved method of forming such connecting construction.

It is a further object of this invention to provide a connecting construction that may be conveniently adapted to suit a wide variety of applications.

An end connection construction for a muffler or the like embodying this invention includes a thin wall shell having a reduced diameter opening formed at one end of the shell. The opening is defined by a section of the shell that has substantially no portion thereof extending in a straight line in a direction normal to the plane of the opening for any significant area around the opening. A

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connecting member is affixed relative to the shell and overlies the opening for connection to another component.

The method of forming the foregoing connection comprises the steps of deforming a closed cross-sectional thin wall member to form a reduced section defining an opening in a single forming operation. A connecting member having a shape complementary to the opening is then fixed to the reduced section in overlying relationship to the opening.

Other objects and advantages of this invention will become more apparent as this description proceeds.

DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of a mufiier for an internal combustion engine exhaust system with portions broken away illustrating a first embodiment of the invention;

FIG. 2 is a partial cross-sectional view, in part similar to FIG. 1, showing two other embodiments of the invention;

FIG. 3 is a partial cross-sectional view showing another embodiment of the invention;

FIG. 4 is a partial cross-sectional view showing a further embodiment of the invention;

FIG. 5 is a partial cross-sectional view showing still another embodiment of the invention;

FIG. 6 is a cross-sectional view showing a still further embodiment of the invention; and

FIG. 7 is a longitudinal cross section of another embodiment of the invention.

DESCRIPTION OF THE INVENTION Referring now in detail to the drawings and in particular to the embodiment shown in FIG. 1, a mufiler for the exhaust system of an internal combustion engine is indicated generally by the reference numeral 11. The mufiler 11 has an outer shell 12 that may be formed conveniently from a single cylindrical piece of thin wall tubing which may be of the seamless or rolled seam type. Any suitable form of baflling or silencing structure may be provided within the outer shell 12 and, since the silencing construction forms no part of the present invention, it will not be described in detail.

The forward end of the outer shell 12 is formed with a deformed partially spherical section 13 that may be formed by swaging, cold forging or any other suitable method. The section 13 is, however, formed in a single operation. As a result of the formation of the section 13, the inlet end of the outer shell 12 forms a reduced diameter circular aperture 14 that is concentric with the longitudinal axis of the outer shell 12. A similar deformed partially spherical portion 15, formed at the outlet end of the outer shell 12, forms a reduced diameter outlet opening 16.

A tubular thin wall gas conduit 17 extends completely through the outer shell 12 and extends through the apertures 14 and 16. The conduit 17 is secured to the deformed portion 13, as by a weld 18. The rear end of the gas conduit 17 may be secured to the deformed portion 15, as by a weld 19. It should be noted that the exposed ends of the conduit 17 form a cylindrical connecting member that is coaxial with the longitudinal axis of the outer shell 12. The forward end of the gas conduit 17, indicated by the reference numeral 21, may function as a means for connection to an exhaust gas pipe (not shown) of an automotive exhaust system. The rear end of the conduit 17 may be cut-off, as at 22 to function as an exhaust outlet at this end of the mufller 11. A mounting flange 23 may be afiixed around the periphery of the outlet end of the conduit 17 adjacent to the cut-off portion 22 and provides with apertures 24 so that the rear end of the mutfier 11 may be supported in a suitable manner.

The described construction results in the formation of a cylindrical connecting section at each end of the mufiler. The connecting sections conveniently may be connected to other tubular conduits or pipes of the exhaust system. It should be noted that the construction shown in FIG. 1 permits such a connection to be formed without the necessity of forming an offset portion or bushing at the adjacent ends of the outer shell 12. Since the ends of the outer shell 12 are formed as a continuous curve with no discontinuities in the embodiment shown in FIG. 1, only a single forming operation is necessary to form the connection. If a bushing were provided by the outer shell itself, more than one forming operation would be required, however, to form the necessary cylindrical section. The same principle may be applied to form other types of connections as exemplified by the following embodiments. It is to be understood, however, that these embodiments are exemplary only of some possible variations and other modifications may be made without departing from the practice of this invention.

Referring now to the embodiment shown in FIG. 2, a muflier 31 is provided with an outer shell 32 that is formed from a thin wall tube. The forward end of the outer shell 32 is formed with a deformed portion 33, which may have the shape of a spherical segment, by a single forming operation, as has been previously described. The forming operation leaves a reduced diameter circular aperture 34 at the mouth of the section 33. A similar deformed section 35 is formed at the other end of the outer shell 32 and results in a circular aperture 36. The apertures 34 and 36 are coaxially disposed with each other as well as with the major portion of the length of the outer shell 32.

Any type of silencing mechanism may be provided within the outer shell 32, however, in this embodiment an inner pipe 37 extends the full length of the outer shell 32 and through the apertures 34 and 36. An inlet connection in the form of a segment of cylindrical thin wall pipe 38 is telescopically received on the forward end of the inner pipe 37. The pipe 38 is slotted, as at 39, and forms a means for connection to an exhaust pipe (not shown) of an automotive exhaust system. The pipe 38, inner pipe 37 and shell portion 33 may be welded to each other around the periphery of the pipe 38. Alternatively, the inner pipe 37 may be spot welded at spaced locations to the pipe 38 and the pipe 38 alone welded to the deformed portion 33.

A similar pipe 41 may be provided at the rear end of the muffler 31. The pipe 41 has a first, reduced diameter portion 42 that telescopically receives the outlet end of the inner pipe 37. A second increased diameter portion 43 is provided downstream from the portion 42 for attachment to a larger pipe (not shown) of the exhaust system. The portion 42 of the pipe 41 may be welded around its periphery to the deformed portion 35 and the corresponding end of the inner pipe 37 may be free to slide within the pipe 41 to compensate for differences in thermal expansion. Again, it is to be understood that different welding techniques may be provided at each end of the muffler, however, it should be noted that cylindrical attachment connections are provided without the necessity of any more than a single forming operation being performed at each end of the outer shell 32.

In the foregoing described embodiments, a small weld area was provided between the adjacent end of the outer shell and the connection. FIG. 3 illustrates an embodiment wherein a larger contact area is provided and this construction lends itself readily to friction welding. In FIG. 3, a portion of a muflier is indicated by the reference numeral 51. The mufller 51 has an outer shell 52 with deformed portion 53 that forms a reduced central aperture 54. The portion 53 has a generally spherical shape and the aperture 54 lies on the longitudinal axis of the shell 52.

An exhaust gas connection 55 has a cylindrical portion 56 that extends away from the shell portion 53 and is concentric with the longitudinal axis of the shell 52. Adjacent the shell portion 53, the connection 55 is provided with a section 57 that has a shape complementary to the shape of the portion 53. The section 57 surrounds and overlies the aperture 54. Since the section 57 is complementary in shape to the deformed portion 53 of the shell 52, these parts may be welded together by friction welding. As is well known, this procedure involves rapidly rotating one piece with respect to the other while exerting an axial pressure thereon.

FIG. 4 illustrates an embodiment similar to FIG. 3 wherein an outlet connection 61 has a portion 62 thereof that is complementary to a deformed portion 63 of an outer shell 64 of a mufiier. In this embodiment, however, an aperture 65 is formed in the portion 63 that is offset from the longitudinal axis of the outer shell 64. This type of construction has particular application when the underbody design of the vehicle in which the exhaust system is used necessitates an angularly disposed outlet connection for the mufiler. The outlet connection 61 in the illustrated embodiment has a cylindrical portion 66 that is coaxially disposed with the aperture 65 and angularly disposed with respect to the longitudinal axis of the shell 64. As in the previously described embodiments, the deformed portion 63 is formed with a single cold forming operation and the portions 62 and 63 are friction welded together.

Referring now to the embodiment of FIG. 5, a mufiler 71 is provided with an outer shell 72 formed from a thin wall piece of cylindrical tubing. One end of the outer shell 72 is provided with a deformed portion 73, which may be formed from a single cold forming operation and has a generally segmental spherical shape. The portion 73 defines a reduced diameter open end 74 of the shell 72. An inner pipe 75 extends through the outer shell 72 and through the aperture 74 in the deformed portion 73. A connection assembly 76 in the form of a tubular thin wall cylindrical pipe has a portion 77 that extends through the aperture 74 and telescopically receives the outer end of the inner pipe 75. A cylindrical end part 78 of the connection 76 is provided for attachment with an exhaust pipe (not shown) of an internal combustion engine exhaust system. The connection portion 77 is upset on each side of the deformed portion 73, as at 79 and 81, around the periphery of the aperture 74 to fix the connection 76 with respect to the shell portion 73. If necessary, the upset portion 81 may be welded to the adjacent surface of the shell portion 73.

The embodiment shown in FIG. 6 is substantially the same as that shown in FIG. 5 with regard to the manner of attachment of the connection to the shell. In this instance, however, the outer shell 91, which is formed from a thin wall cylindrical piece of tubing, has a deformed end portion 92 that is substantially planar and defines a reduced central opening 93. This shape also may be formed in a single operation. An exhaust connection 94 is atfixed to the end portion 92 within the opening 93 in the same manner as in FIG. 5 and this construction will not be described again in detail.

In FIG. 7 the mufiier 101 has a one piece outer shell 103 with inlet and outlet ends 105 and 107 which are progressively decreased in diameter to terminate in circular edges 109 and 111. Extending through the shell is a gas flow tube 113 and this has a pair of outer annular enlargements 115 and 117 and a pair of inner and larger annular enlargements 119-and 121. The inner and outer enlargements are adjacent to each other and the inner enlargements have surfaces which receive and blend with the terminal ends of the shell portions 105 and 107. The circular end openings 109 and 111 fit in the reduced diameter sections 123 and 125 between the inner and outer en largements, which sections are substantially the same size as the balance of the tube 113. Spotwelds 127 unite the shell and the enlargements 119 and 121. Thus, the shell is firmly secured to and supported by the enlargements on the tube 113 which furnish mechanical support for the shell to prevent undesired or excessive deflection. The construction is such as to permit substantial dimensional tolerances in manufacture without interferring with the integrity of assembly.

The tube 113 is provided with a patch of louvers 129 and these open into the closed end of a tuning passage 131 which is formed by a shell 133 that is concentric with the tube 113 and pinched to it in a gas-tight joint at 135. The other end of the shell 133 is open as seen at 137 to contact the passage 131 with the chamber 139 whereby a tuned Helmholtz resonator construction fed by the louver patch 129 may be formed. The downstream end of the shell 133 may be slit and deformed into contact as seen at 141 with the tube 113 and spotwelded to it for additional support.

A bracket 143 may be secured on the tube 113 for mounting purposes.

In operation, it is apparent that gas enters the inlet end 145 and flows directly through the tube 113 to be discharged at the bevelled outlet end 147 in the tube. Within the shell 103 high frequencies are attenuated to some degree by the louver patch 129 acting in conjunction with the chamber 139. Tuning to remove predetermined lower frequencies may be obtained by adjustment of the size and length of the passage 131 in relation to the volume of the chamber 139.

I claim:

1. A mufiier comprising an elongated one piece outer shell having a body portion of substantially uniform width along its length and end portions progressively decreasing in width and terminating in circular end edges, a gas flow tube extending through said shell and having an outer diameter substantially the same as the diameter of the circular edges, said tube having annular enlargements on the outside of the shell and engaging the ends of the shell adjacent said circular edges, said gas flow tube having larger annular enlargements located inside the shell and engaging the ends of the shell adjacent the circular edges and in surface contact with the inside of the ends of the shell, the ends of the shell being spotwelded to the inner annular enlargements, said annular enlargements being spaced from the ends of the tube and comprising single wall thickness curved tube portions located radially outwardly from said outer diameter.

2. A muffler or the like comprising an outer shell, said outer shell being formed from a piece of thin walled tubing having a substantially cylindrical shape along a major portion of its length and terminating at each end in integral end portions, each of said end portions of said outer shell curving inwardly from said cylindrical portion toward and defining a respective circular opening at the inner termination thereof, each of said end portions defining a substantially continuous curved surface extending from said cylindrical portion to the respective opening, the circular openings in said end portions being coaxially disposed and substantially coaxial with respect to said cylindrical portion, tubular gas flow means extending through and fitting said circular openings, said tubular means including a pair of annular enlargements adjacent each end spaced apart only enough to receive said shell end portions between the enlargements whereby said enlargements serve as means to connect the shell to the tubular means.

3. An end connection for a muffler or the like comprising a thin wall tubular outer shell, said outer shell having a cylindrical portion terminating at one end in an integral end portion, said end portion curving inwardly from said cylindrical portion toward and defining a circular opening at the inner termination of said end portion, said portion defining a substantially continuous curved surface extending from said cylindrical portion to said opening, a substantially constant diameter tubular member extending through said opening, said tubular member having a first portion disposed within said opening and having substantially the same diameter as said opening, said tubular member having diametrically enlarged second and third portions on opposite sides of said first portion, said second and third portions of said tubular member being in engagement with opposite sides of said end portion around said opening to provide means for atfixing said tubular member to said end portion adjacent said openmg.

4. An end connection for a muffler or the like comprising an outer shell, said outer shell being formed from a single piece of thin walled tubing having a substantially cylindrical shape along a major portion of its length and terminating at one end in an integral end portion, said end portion of said outer shell curving inwardly from said cylindrical portion toward and defining a respective circular opening at the inner termination thereof, said end portion defining a substantially continuous curved surface extending from said cylindrical portion to the opening, a substantially constant diameter tubular means extending through said outer shell and through said circular opening, said tubular means having a first part located inside said circular opening of substantially the same diameter as said circular opening, said tubular means having second and third parts on opposite sides of said first part, each of said second and third parts being larger than said constant diameter and comprising a first portion extending radially outwardly from said first part adjacent said opening and a second reentrant portion extending from the termination of said first portion radially inwardly, each of said first portions being in engagement with the respective adjacent side of said outer shell end portion for affixing said tubular means relative to said outer shell.

5. An end connection as set forth in claim 4 wherein said tubular means comprises inner and outer tubular members, said first, second, and third parts being formed only in said outer member.

6. An end connection as set forth in claim 4 wherein the end portion of said shell has a substantial surface area engagement with the inner of said second and third parts.

7. An end connection as set forth in claim 6 including spotwelds uniting said shell and said part in the area of said surface engagement.

8. An end connection as set forth in claim 3 further including a second tubular member telescopically received within the first mentioned tubular member and extending into the outer shell.

9. An end connection as set forth in claim 8 wherein the end portion has the shape of a segment of a sphere.

References Cited UNITED STATES PATENTS 1,376,957 5/1921 MacKenzie et al. 1,685,302 9/1928 Tyler. 1,735,789 11/ 1929 Powell. 1,800,354 4/1931 Powell. 2,405,201 8/1946 Franck 29-422 2,624,418 1/1953 Bourne 18l6l XR 2,710,677 6/1955 Ferris 138107 XR 3,064,336 11/ 1962 Powers et a1. 3,082,841 3/1963 Powers. 3,219,141 11/1965 Williamitis. 3,388,770 6/1968 Straw 181-72 ROBERT S. WARD, 111., Primary Examiner US. Cl. X.R. 

